Air pollutant concentrations

About: Air pollutant concentrations is a research topic. Over the lifetime, 1652 publications have been published within this topic receiving 36138 citations.

Measurements of Concentrations of Air Pollutants

Abstract: Publisher Summary Measurements of air pollutant concentrations are normally carried out at fixed site monitoring stations. An alternative for some pollutants is to attach personal monitors to volunteers to measure personal exposure directly. Such measurements can differ greatly from fixed site measurements of concentration as the population spend majority of their time indoors, where concentrations can differ appreciably from those out-of-doors. Measurements of air pollutant concentrations are best considered in the context of the entire air quality management process. In general, the purpose of local air quality management is to safeguard human health, and hence an understanding of the overall process is valuable. The strategy uses monitoring to provide information on the present levels of air pollution and involves the use of air quality standards to provide a benchmark of acceptable air quality. If measured concentrations are comfortably within health-based air quality standards, then little action may be required. However, in urban areas throughout the world, concentrations of some air pollutants are liable to exceed air quality standards and development of control strategies is essential. Such control strategies entail reduction of emissions from one or more categories of source, and before embarking on such a policy, the regulatory authority will wish to have quantitative knowledge of the likely benefits of the strategy, and probably have conducted a cost/benefit appraisal in which the cost-effectiveness of different control strategies can be compared.

Accountability assessment of regulatory impacts on ozone and PM2.5 concentrations using statistical and deterministic pollutant sensitivities

Abstract: Since the 1990 Clean Air Act Amendments, the USA has seen dramatic decreases in air pollutant emissions from a wide variety of source sectors, which have led to changes in pollutant concentrations: both up and down. Multiple stakeholders, including policy-makers, industry, and public health professionals, seek to quantify the benefits of regulations on air pollution and public health, a major focus of air pollution accountability research. Two methods, one empirical, the other based on a chemical transport model (CTM), are used to calculate the sensitivities of ozone (O3) and particulate matter with diameters less than 2.5 μ m (PM2.5) to electricity-generating unit (EGU) and mobile source emissions. Both methods are applied to determine impacts of controls on daily concentrations (which are important in assessing acute health responses to air pollution), accounting for nonlinear, meteorologically, and emission-dependent responses of pollutant concentrations. The statistical method separates contributions of nearby EGU, regional EGU, and mobile source emissions on ambient city-center concentrations. Counterfactual emissions, an estimate of emissions under a scenario where no new controls were implemented on local EGU sources after 1995, regional EGUs after 1997, and mobile sources after 1993, are combined with these sensitivities to estimate counterfactual concentrations that represent what daily air quality in Atlanta, GA would have been had controls not been implemented and other emissions-reducing actions not been taken. Regulatory programs are linked with reduced peak summertime O3, but have had little effect on annual median concentrations at the city-center monitoring site, and led to increases in pollutant levels under less photochemically-active conditions. The empirical method and the CTM method found similar relationships between ozone concentrations and ozone sensitivity to anthropogenic emissions. Compared to the counterfactual between 2010 and 2013, the number of days on which O3 (PM2.5) concentrations exceeded 60 p p b (12.0 μ g m −3) was reduced from 396 to 200 (1391 to 222). In 2013, average daily ambient O3 and PM2.5 concentrations were reduced by 1.0 p p b (2 %) and 9.9 μ g m −3 (48 %), respectively, and fourth highest maximum daily average 8-h O3 was reduced by 14 p p b. Comparison of model-derived sensitivities to those derived using empirical methods show coherence, but some important differences, such as the O3 concentration where the sensitivity to NOx emissions changes sign.