The development of local ambient air quality standards: A case study of Hainan Province, China

The ambient air quality standard(AAQS)is a vital policy instrument for protecting the environment and human health.Hainan Province is at the forefront of China's efforts to protect its ecological environment,with an official goal to achieve world-leading air quality by 2035.However,neither the national AAQS nor the World Health Organization guideline offers sufficient guidance for improving air quality in Hainan because Hainan has well met the former while the latter is excessively stringent.Consequently,the establishment of Hainan's local AAQS becomes imperative.Nonetheless,research regarding the development of local AAQS is scarce,especially in comparatively more polluted countries such as China.The relatively high background values and significant interannual fluctuations in air pollutant concentrations in Hainan present challenges in the development of local AAQS.Our research proposes a world-class local AAQS of Hainan Province by reviewing the AAQS in major countries or regions worldwide,analyzing the influence of different statistical forms,and carefully evaluating the attainability of the standard.In the proposed AAQS,the annual mean concentration limit for PM2.5,the annual 95th percentile of daily maximum 8-h mean(MDA8)concentration limit for O_(3),and the peak season concentration limit for O_(3) are set at 10,120,and 85μg/m^(3),respectively.Our study indicates that,with effective control policies,Hainan is projected to achieve compliance with the new standard by 2035.The implementation of the local AAQS is estimated to avoid 1,526(1,253–1,789)and 259(132–501)premature deaths attributable to longterm exposure to PM2.5 and O_(3) in Hainan in 2035,respectively.

Characterization,reactivity,source apportionment,and potential source areas of ambient volatile organic compounds in a typical tropical city

Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).

Dynamic grouping of heterogeneous agents for exploration and strike missions

The ever-changing environment and complex combat missions create new demands for the formation of mission groups of unmanned combat agents.This study aims to address the problem of dynamic construction of mission groups under new requirements.Agents are heterogeneous,and a group formation method must dynamically form new groups in circumstances where missions are constantly being explored.In our method,a group formation strategy that combines heuristic rules and response threshold models is proposed to dynamically adjust the members of the mission group and adapt to the needs of new missions.The degree of matching between the mission requirements and the group’s capabilities,and the communication cost of group formation are used as indicators to evaluate the quality of the group.The response threshold method and the ant colony algorithm are selected as the comparison algorithms in the simulations.The results show that the grouping scheme obtained by the proposed method is superior to those of the comparison methods.