An Analytical Investigation of Ozone Episodes in Bangu, Rio de Janeiro

Elevated ozone disrupts mating boundaries in drosophilid flies

Animals employ different strategies to establish mating boundaries between closely related species, with sex pheromones often playing a crucial role in identifying conspecific mates. Many of these pheromones have carbon-carbon double bonds, making them vulnerable to oxidation by certain atmospheric oxidant pollutants, including ozone. Here, we investigate whether increased ozone compromises species boundaries in drosophilid flies. We show that short-term exposure to increased levels of ozone degrades pheromones of Drosophila melanogaster, D. simulans, D. mauritiana, as well as D. sechellia, and induces hybridization between some of these species. As many of the resulting hybrids are sterile, this could result in local population declines. However, hybridization between D. simulans and D. mauritiana as well as D. simulans and D. sechellia results in fertile hybrids, of which some female hybrids are even more attractive to the males of the parental species. Our experimental findings indicate that ozone pollution could potentially induce breakdown of species boundaries in insects.

Possible influence of shipping emissions on metals in size-segregated particulate matter in Guanabara Bay (Rio de Janeiro, Brazil)

In the world of growing maritime fleets, ships powered by fossil fuels are being widely used that are responsible for atmospheric emissions such as particulate matter (PM). When inhaled, these can cause serious injury to the body and affect internal organs, because the particle size is on a tiny scale. The International Convention for the Prevention of Pollution from Ships (MARPOL) regulates the standards for emissions from marine diesel engines. However, although they pose risks to human health and the environment, the metals present in PM are not covered by Brazilian national current legislation. This study is based on the results of sampling of PM in the atmosphere of Guanabara Bay, Rio de Janeiro, Brazil, by means of the MOUDI cascade impactor, followed by acid opening of the collected PM and subsequent chemical analysis by ICP-MS for the determination of Ba, Ca, Cd, Co, Cu, Cr, Fe, Mg, Mn, Ni, Pb, V, and Zn. In coarse particles, the mean values ranged from 0.11 ng m^-3 for Ba to 24.9 ng m^-3 for Fe; in fine particles, from 0.07 ng m^-3 for Co to 25.0 ng m^-3 for Fe; and in ultrafine particles, from 0.11 ng m^-3 for Ba to 9.71 ng m^-3 for Fe. Finally, the nanoparticles (Ba and Ca) were not detected and the maximum value obtained was 5.32 ng m^-3 for Mn.

Impact of the Petrochemical Complex on the Air Quality of an Urban Area in the City of Rio de Janeiro, Brazil

In the city of Rio de Janeiro (Brazil), the districts located in the northern area are considered the most critical regarding ozone levels year-round. In this study, the potential factors that contribute to high levels of ozone in the district of Irajá were investigated. The obtained results clearly showed that, in spite of the high correlation of ozone concentrations with wind speed and temperature, ozone episodes depend on the ratios of volatile organic compounds (VOCs) to nitrogen oxides (NO_x) rather than on the individual VOC and NO_x levels, as expected for the VOC-controlled condition typical of the urban area of Rio de Janeiro. Moreover, high VOCs/NO_x ratios are highly dependent on the transport of air masses. When pollutants are transported from urban areas with heavy vehicular flux and high NO_x concentrations, ozone levels are reduced. When air masses are transported from the industrial petrochemical area, NO_x levels are relatively low, and ozone episodes are frequent.

Understanding high tropospheric ozone episodes in Bangu, Rio de Janeiro, Brazil

This study investigates the potential factors that contribute to frequent high levels of ozone in Bangu, one of the most critical areas in the city of Rio de Janeiro, regarding ozone levels and air quality. Speciated non-oxygenated volatile organic compounds (VOCs) were measured using method TO-15 (US EPA). The measured concentrations and kinetic and mechanistic analysis of VOC reactivity showed that alkanes were the most important compounds. Ozone concentrations were simulated for a base case representing a day with high ozone levels. Simulated results and statistical multivariate analysis showed that the high ozone concentrations did not seem to be closely related to local emissions but rather were related to pollutant transport and low measured NO_x levels and were triggered by photochemical activity. The differences between weekdays and weekends were also investigated, showing that ozone concentrations were also higher during weekends, mainly on Sunday, when the diesel heavy vehicle fleet was reduced and lower NO emissions were observed. The VOC/NO_x ratios correspond to a VOC-limited process, which leads to higher ozone concentrations under low NO_x conditions.

Monitoring of air quality before the Olympic Games Rio 2016

For the accomplishment of Olympic and Paralympic Games in Rio de Janeiro city (Rio 2016), the government of the Rio de Janeiro state has undertaken to monitor air quality before and during the events. In Beijing, China, and Athens, Greece, the air quality was monitored in Olympic venues in order to evaluate the athletes' performance in relation to the environment in which they were exposed. This study has the same proposal to Rio de Janeiro, Brazil. The air quality scenario of the three previous years (2013, 2014, 2015) of Rio 2016 was considered. Coarse (PM10) and fine (PM2.5) particles and O3 were monitored continuously on the stations located near to competition venues, as required by International Olympic Committee (IOC). The levels registered ranged from 6 to 96 μg m-3 for PM10, 1 to 44 μg m-3 for PM2.5 and 121 to 269 μg m-3 for O3. These concentrations exceeded the national and international air quality standards. These high concentrations are associated with uncountable civil works to build Olympic arenas and the urban mobility´s improvement. However, the concentrations for all the pollutants monitored in Rio de Janeiro city were in lower concentrations than in Beijing Olympic Games 2008.