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Abstract: China's air pollution control policies during the 12th Five Year Plan (2011–2015) are characterized by the targets of 10% nitrogen oxides (NO x ) reduction and 8% sulfur dioxide (SO2) reduction from the 2010 levels. In this study, the Community Multi-scale Air Quality (CMAQ) modeling system was used to evaluate the impact of only SO2, only NO x , and joint SO2/NO x control measures on particulate matter pollution, the greatest concern for urban air quality in China. Four emission scenarios were developed for 2015, including a business-as-usual scenario, a reference NO x control scenario based on the governmental plan, an accelerated NO x control technology scenario, and a scenario assuming joint controls of NO x and SO2 based on the governmental plan. Under the planned NO x control measures, the annual mean concentrations of particulate matter less than or equal to 2.5 μm (PM2.5) decline by 1.5–6 μg m−3, i.e. 1.6%–8.5%, in the majority of eastern China. The largest reduction occurs in the middle reach of the Yangtze River. Under accelerated NO x control measures, the annual average PM2.5 concentration reductions (compared with the business-as-usual scenario) in eastern China are 65% higher than the reductions under planned control measures. The unusual increase of PM2.5 concentrations in the North China Plain and the Yangtze River Delta during January after the reductions of NO x emissions was an integrated effect of excessive NO x , the ammonia-rich inorganic aerosol chemistry, and the non-methane volatile organic compounds (NMVOC) sensitive photochemical regime. Under the joint controls of NO x and SO2, the annual mean PM2.5 concentrations decline over 3 μg m−3, i.e. 3.2%–13%, in the majority of eastern China, and some areas in the middle reach of the Yangtze River have reductions as large as 6–8.3 μg m−3, i.e. 5.0%–13%. The average PM2.5 concentration reductions in eastern China are 1.20 μg m−3, 3.14 μg m−3, 3.57 μg m−3, 4.22 μg m−3 in January, May, August, and November, respectively. The corresponding declining rates are 2.3%, 12.2%, 14.3%, and 8.1%, respectively. More stringent policies should be implemented in winter to reduce the heavy pollution periods. The annual average PM2.5 concentration reductions in three major city clusters are comparable with the average reductions of eastern China. Stringent regional control policies are required for the significant improvement of particulate air quality in major city clusters. [Copyright &y& Elsevier]

Abstract: The air quality impacts of aviation are becoming increasingly important given their impact on human health and the projected growth of aviation. In the United States, the government has set targets to manage and reduce the environmental impacts of aviation. In an environmental policy assessment context it is often necessary to rapidly evaluate many possible scenarios, and quantification of uncertainty is important. This makes direct application of comprehensive air quality models such as the Community Multiscale Air Quality (CMAQ) modeling system impractical due to computational cost. Here we develop a response surface model (RSM) – a form of rapid surrogate model – of the impact of aviation emissions on air quality in the United States. We develop an RSM design space and populate it with results from 46 CMAQ simulations, and perform cross-validation of the resultant RSM. The RSM models present-day as well as future impacts amid changing population and non-aviation emissions sources. This enables rapid estimates of the (particulate matter) air quality and human health impacts of aviation emissions scenarios. Cross-couplings between precursor gaseous emissions and PM2.5 species are found, consistent with competition for atmospheric ammonia. We apply the RSM to quantify the human health benefits of emissions reductions in 2018. Using the RSM we estimate that in 2005, aviation landing and takeoff emissions cause ∼195 [90% CI: 80–340] early deaths, while the same emissions cause ∼350 [90% CI: 145–610] mortalities in 2018. An emissions tradespace between aviation NO x and SO x emissions is constructed. It is found that with fleet-wide desulfurization of jet fuel, a 35% reduction in aviation NO x emissions would result in maintaining the same level of aviation-attributable early deaths in 2018 relative to 2005 levels, while an 80% reduction in NO x emissions would half aviation-attributable early deaths. [Copyright &y& Elsevier]

Abstract: The potential adverse human health impacts of emissions from UK airports have become a significant issue of public concern. We produce an inventory of UK airport emissions – including emissions from aircraft landing and takeoff operations, aircraft auxiliary power units (APUs) and ground support equipment (GSE) – with quantified uncertainty. Emissions due to more than 95% of UK passenger enplanements are accounted for. We apply a multi-scale air quality modelling approach to assess the air quality impacts of UK airports. Using a concentration-response function we estimate that 110 (90% CI: 72–160) early deaths occur in the UK each year (based on 2005 data) due to UK airport emissions. We estimate that up to 65% of the health impacts of UK airports could be mitigated by desulphurising jet fuel, electrifying GSE, avoiding use of APUs and use of single engine taxiing. Two plans for the expansion of UK airport capacity are examined – expansion of London Heathrow and new hub airport in the Thames Estuary. Even if capacity is constrained, we find that the health impacts of UK airports still increases by 170% in 2030 due to an increasing and aging population, increasing emissions, and a changing atmosphere. We estimate that if Heathrow were to be expanded as per previous UK Government plans, UK-wide health impacts in 2030 would increase by 4% relative to the 2030 constrained case, but this increase could become a 48% reduction if emissions mitigation measures were employed. We calculate that 24% of UK-wide aviation-attributable early deaths could be avoided in 2030 if Heathrow were replaced by a new airport in Thames Estuary because the location is downwind of London, where this reduction occurs notwithstanding the increase in aircraft emissions. A Thames hub airport would (isolated from knock-on effects at other airports) cause 60–70% fewer early deaths than an expanded Heathrow, or 55–63% fewer early deaths than an unexpanded Heathrow. Finally, replacing Heathrow by a Thames Estuary airport combined with emissions mitigation measures would reduce UK-wide aviation-attributable early deaths by 56% in 2030 while increasing aircraft movements, which would represent aviation causing about the same level of adverse health impacts as today in absolute terms. We note that because aviation emissions are included in the EU Emissions Trading Scheme, all options are CO2-neutral in terms of direct emissions (but not climate-neutral). [Copyright &y& Elsevier]

Abstract: To reduce air pollution levels in Santiago, Chile on days when the weather is expected to create poor ventilation conditions and increased air pollutant concentrations, the responsible authorities impose temporary restrictions on motor vehicles and certain industrial activities. We estimate the impact of these restrictions on the city''s air quality using data collected by a network of monitoring stations. The estimates show that the restrictions do reduce the average concentrations of coarse and fine particulate matter, carbon monoxide and nitrogen oxide (both gases are emitted mainly by vehicles). However, no significant changes were found in the sulfur dioxide concentrations, which are primarily the result of industrial processes. [Copyright &y& Elsevier]

Abstract: Concentrations of 13 organic source markers (10 polycyclic aromatic hydrocarbons and 3 hopanes) are reported from time-integrated samples (24-h and sub-daily) collected near a highway in Las Vegas, NV. Sample selection for assessing source impacts from the roadway was completed using the wind regression model Air Pollution Transport to Receptor model (EPA APTR 1.0). The model uses a kernel smoothing method for estimating source sectors (sector apportionment) of chemicals across wind speeds and wind directions. The model was applied using semi-continuous (5-min averaging time) pollutant data (black carbon (BC), CO, NO2, and NOx) and meteorological data. Using simple screening criteria to identify source impacts (>30% sector apportionment from the roadway and errors in the estimated sector apportionment <30%), sector apportionment results were consistent with organic source marker concentrations representative of motor vehicle exhaust (e.g., benzo(g,h,i)perylene and hopane). Results demonstrated the use of APTR to identify source-impacted time intervals when compared with filter samples analyzed for organic source markers. [Copyright &y& Elsevier]