Indoor and Outdoor Air Pollution in Doha - cases of schools and residences

The World Health Organization (WHO) attributes air pollution to 1 in 8 deaths worldwide, where exposure to indoor air pollutants is a significant contributor to incidences of heart disease, respiratory problems, and cancer (WHO, 2014). Since people spend the major part of the day indoors - especially in Qatar -, indoor air quality (IAQ) is a significant factor affecting their overall pollutant exposure via the respiratory-inhalation pathway. IAQ is mainly determined by the geographical location of a building, its proximity to outdoor pollutant sources such as industry, construction activities, traffic or natural pollutant sources (e.g. desert sand particulates), as well as the building characteristics itself (building envelope, air tightness, ventilation/air conditioning system). Indoor sources like decoration and furniture, as well as indoor activities like cleaning and cooking also affect IAQ. Recently, the WHO ranked Qatar second position worldwide of countries with the highest ambient PM2.5 exposure (WHO, 2014). The issue can therefore be regarded as of great significance to public health for the citizens of Qatar, and therefore warrants scientific study and potential mitigation of excessive PM2.5 exposure. In particular, the young citizens of Qatar are especially susceptible to the impacts of PM2.5 inhalation due to their early stage of physiological development. A building can function as a protective shelter for poor outdoor air quality, but without a dedicated IAQ enhancement strategy, buildings may not automatically lead to a reduced indoor exposure to air pollutants, including PM2.5, as well as other potentially harmful pollutants including: oxides of nitrogen and sulphur (NO2, SO2); ozone (O3), natural radiation (radon, Rn); microorganisms (bacteria and fungal spores); a range of volatile organic compounds, and hydrocarbons. This study aimed to characterise IAQ of Qatar's indoor environments, with a particular focus on schools and residences with consideration of outdoor air quality (OAQ) conditions. Simultaneous IAQ/OAQ measurements have been conducted using established reference methods and sampling techniques specifically developed for IAQ studies. PM10, PM2.5 and ultrafine particle concentrations, aerosol size distribution and particle elemental composition have been measured. Volatile organic compounds, aldehydes, NO2, SO2 and O3 were monitored. CO2, temperature and relative humidity were also monitored, and the air exchange rate between indoor and outdoor environments has been assessed. Semi-volatile organic compounds, such as polycyclic aromatic hydrocarbons, phthalates and flame retardants have been quantified in order to identify specific sources of contamination as derived from combustion and/or building material emission sources. Three school classrooms and associated school-pupil homes were selected for conducting IAQ assessments in order to determine pupil exposure levels to air pollutants over a 24-hour period. Volunteers were equipped with personal exposure monitors for determining their location and activity-dependent air pollutant exposure levels. The first measurement campaign of the research project was conducted in May, 2017. Three classrooms were monitored and five residences, as well as the outdoor location in the school's garden. The results indicate that the indoor concentrations of VOCs, aldehydes and PAHs exceeded the outdoor levels, and that pollutants concentration in residences were consistently higher than in the school classrooms. In terms of particulate matter (PM2.5) the opposite trend was observed. The indoor PM2.5 levels were far lower than the reference outdoor concentration. Regarding the comparison of school class rooms and homes, the same trend as in the case of VOCs was observed. Namely, the PM2.5 levels in homes were consistently higher than in the school classrooms. Overall, the results show that indoor environments represent a protective shelter against the outdoor particulate air pollution ion Qatar. The indoor air quality is determined mainly by pollution sources indoors - particularly in residences due to the presence of more intensive and versatile emission sources - including furniture, decorations, use of air refreshers; as well as activity generated emissions by the inhabitants like cooking, cleaning, or smoking. The second measurement campaign will be conducted in December 2017, when new data will be collected under different seasonal conditions i.e. mild temperatures, where buildings typically have more ventilation with the outdoor environment, and where higher ingress of outdoor air pollution may be expected. The authors would like to thank Qatar National Research Fund (QNRF) for funding and supporting this project under the National Priorities Research Program (NPRP) award number NPRP 8-202-3-043.qscienc

Polycyclic aromatic hydrocarbons in dust from the indoor environment of Qatar

Polyaromatic Hydrocarbons (PAHs) concentrations in dust trapped on air conditioning unit filters operating in residential and workplace locations in Doha, Qatar were sampled and measured. Fourteen samples were collected and their PAH congener profile were quantified using gas chromatography–mass spectrometry (GC-MS). The results showed that the medians of ΣPAH16, which include seven carcinogenic components (ΣPAH7), were 214.7 ng g− 1 and 129.2 ng g− 1 of dust respectively for the residential samples, and 224.4 ng g− 1 and 137.9 ng g− 1 respectively for dust samples collected in an office workplace environment. Among all samples, benzo (b) fluoranthene (BBF) and benzo (a) pyrene (BAP) were the dominant congeners in both the residential and workplace samples, representing 18.2% and 16.9% of the ΣPAH16, respectively. Factors of correlation were calculated for various PAHs, and showed that lighter molecular weight PAHs have a significant positive correlation with heavier congeners within the residential samples, while workplace samples showed a negative correlation with BAP, Indeno (1,2,3-cd) pyrene (IND), and Dibenz (a,h) anthracene (DBA). Benzo (a) pyrene equivalent (BAPe) was used to assess the risk of human exposure to PAH inhalation. BAPe estimates for residences sampled averaged 0.019 μg g− 1, with a maximum of 0.063 μg g− 1 of dust, while workplace estimates averaged at 0.056 μg g− 1 with a maximum of 0.148 μg g− 1. Source apportionment assessment indicated that most residential and workplace PAHs samples have a pyrogenic origin with few showing evidence of petrogenic origins. All quantified PAHs concentrations and estimated BAPe in Qatar indoor dust samples are well below reported values elsewhere in the world

Field test of available methods to measure remotely SO2 and NOx emissions from ships

Methods for the determination of ship fuel sulphur content and NOx emission factors based on remote measurements have been compared in the harbour of Rotterdam and compared to direct stack emission measurements on the ferry Stena Hollandica. The methods were selected based on a review of the available literature on ship emission measurements. They were either optical (LIDAR, DOAS, UV camera), combined with model based estimates of fuel consumption, or based on the so called ‘sniffer’ principle, where SO2 or NOx emission factors are determined from simultaneous measurement of the increase of CO2 and SO2 or NOx concentrations in the plume of the ship compared to the background. The measurements were performed from stations at land, from a boat and from a helicopter. Mobile measurement platforms were found to have important advantages compared to the landbased ones because they allow to optimize the sampling conditions and to sample from ships on the open sea. Although optical methods can provide reliable results it was found that at the state of the art, the “sniffer” approach is the most convenient technique for determining both SO2 and NOx emission factors remotely. The average random error on the determination of SO2 emission factors comparing two identical instrumental set-ups was 6%. However, it was found that apparently minor differences in the instrumental characteristics, such as response time, could cause significant differences between the emission factors determined. Direct stack measurements showed that about 14% of the fuel sulphur content was not emitted as SO2. This was supported by the remote measurements and is in agreement with the results of other field studies.JRC.H.2-Air and Climat

Measurements of air pollution emission factors for marine transportation in SECA

The chemical composition of the plumes of seagoing ships was investigated during a two weeks long measurement campaign in the port of Rotterdam, Hoek van Holland, The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg-1 fuel) was provided. The concerned main atmospheric components were SO2, NO2, NOX and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was measured. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 34 vs. 30 g kg-1 fuel), and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factor. The slope of the regression line, 2x1018 (kg fuel)-1, provides the average number of sulphate particles from 1 kg sulphur burnt with the fuel, while the intercept, 0.5x1016 (kg fuel)-1, gives the average number of primary particles (mainly soot and ash) formed during the burning of 1 kg fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that approx. 144 g of sulphate particles were emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was 42 nm.JRC.H.2-Air and Climat

A Metric for Health Effects Studies of Diesel Exhaust Particles

A metric for the assessment of health effects of diesel exhaust particles is proposed and a methodology to determine it from experimental data is presented. The metric treats separately the emitted volatile and non-volatile mass fractions. The appropriate metric for health related effects of the non-volatile mass fraction (primarily soot), termed the physical effect, is taken to be the particle (active) surface area distribution. The corresponding metric of the volatile mass fraction (unburned hydrocarbons, sulphates, nitrates), termed the chemical effect, is taken to be the volatile mass concentration distribution of the nucleation mode and the mass concentration distribution of the condensed volatiles on the accumulation mode. The latter is proportional to distribution of the (active) surface area concentration of the accumulation mode. A methodology to derive the distributions (metric) from filter-based mass and number distributions measurements is suggested. Nine experimental particle number distributions, emitted by light duty Euro 1, 3 and 4 vehicles, with and without diesel particle filters or catalysts, at different speeds and using different fuels, are analyzed to determine characteristic volatile mass and non-volatile surface area concentration distributions. These distributions become the required input distributions for lung deposition calculations, thereby defining the appropriate metric to estimate health effects of diesel exhaust particles.JRC.H.4-Transport and air qualit

Size-Distribution Dependent Lung Deposition of Diesel Exhaust Particles

Lung deposition fractions of nine experimental particle number distributions emitted by various light duty diesel vehicles with different after-treatment devices and fuels were calculated with a stochastic lung deposition model. The emitted volatile and non-volatile mass fractions were treated separately as the corresponding biological response in the human respiratory tract differs. The health related effects of the volatile mass fraction, referred to as the chemical effect, were associated with the deposited volatile mass. The deposited volatile mass depends on the total emitted volatile mass concentration, on its distribution (mass median diameter of nucleation mode and surface area median of the accumulation mode), and on the ratio of the volatile mass in the nucleation and accumulation modes. The effect of the non-volatile mass fraction, referred to as the physical effect, was associated with the surface area distribution of the accumulation mode. The deposited surface area of the non-volatile fraction depends on its emitted concentration and on the surface area median diameter of the size distribution. The calculations suggest the importance of selecting the appropriate distribution (surface, volatile or non-volatile mass) for an assessment of the health effects of diesel exhaust particles, and the importance of combined particulate matter and number distribution measurements.JRC.H.4-Transport and air qualit

Elemental compositions of particulate matter retained on air condition unit’s filters at Greater Doha, Qatar

© 2019, The Author(s). Elemental composition of airborne dust samples retained by internal filters of air condition units (ACUs) was determined at 12 locations of Doha city, state of Qatar. Twenty-four elements: Al, Ca, Mg, Fe, Na, K, Ti, Zn, P, Sr, Mn, Ba, Cu, Cr, Ni, Pb, V, Mo, Li, Co, Sb, As, Cd, Be, were analysed by ICP-OES technique after acid digestion of the samples. The analysed components reflect 20.6% of the total sample mass. Similar or lower concentration values have been found for As, Cd, Cr, Cu, Mn, Ni, Pb, V, Zn, Al, and Fe compared to the international context of upper crust concentrations, NIST SRM (urban dust), published local dust information of outdoor, and surface terrestrial deposit (STD) counted for 7.2, 0.7, 91.8, 192.8, 369.7, 68.6, 65.3, 52.1, 824.3, 19,791, 20,508 mg/kg, respectively. The coefficient of correlation (p ≤ 0.05) showed significant association of ACUs dust elemental compositions with the main components of the local earth crust and surface deposits, ranging from the lowest 0.77 (Mg–Fe) to the highest 0.98 (Al–Fe), while Ni and V, typical anthropogenic pollutants, are also strongly correlated (0.86). These strong correlation relationships can be interpreted as the contribution of outdoor particulate to the indoor dust. Dendrogram of metal/Al ratios, based on Euclidean distance calculation and average linkage clustering method, distinguished three typical groups. Studying the enrichment factors of the three groups indicated elevated levels of Zn (131), Pb (49), Cu (32), Cd (8) and Ni (5) found indoors compared to the background composition of STD especially at locations in the industrial zone. The major elemental composition of the samples reflects the typical mineral composition of the local dust, while the trace composition demonstrates the influence of indoor sources. The collected ACU filter dust samples show significant contribution of outdoor mineral particles, non-exhaust traffic emission, industrial sources, as well as the influence of indoor activity such as smoking