Physicochemical model and kinetics of pesticide constituent evaporation out of multi-ingredient polydisperse aerosols

Abstract

: Contamination of the atmosphere by pesticides is an inevitable consequence of their application for plant protection, and a substantial part of pesticide pollutants exists as airborne particles. Evaporation of particulate matter is often the main pathway that provides the removal of intraparticle pesticide, and, thus, the detoxication of aerosol pollutants occurs. On the other hand, evaporation causes entry of pesticide vapour into the air, and may result in pesticide contamination of the atmosphere.The known models of particle evaporation cannot be directly used for realistic multi-ingredient pesticide formulations because the data on the physicochemical properties of particle constituents are usually absent or unavailable. A simpliÐed model is derived which describes the evaporation of the pesticide out of both an individual particle and a polydisperse aerosol mixture, taking into account the pesticide vapour pressure-temperature dependence, initial content of pesticide in particles, aerosol sizes, and degree of particle polydispersity, etc.. The temperature dependencies of evaporation rates for both the polydisperse aerosol mixtures, and the particles of diameter km, and, then, of an arbitrary d m B 2 diameter were determined for malathion, parathion-methyl, phosalone, propiconazole, and ethaphos formultions. The unknown vapour concentration or pressure-temperature dependencies were evaluated for some pesticides, and the evaporation life-times of particles were estimated under ambient conditions.

Photochemical Decomposition of Pesticide Chemicals in Aerosol Particles and Thin Films Relevant to Environmental Conditions

“…One of the characteristic properties of high disperse substances is that only the low-volatile organic (pesticide) compounds with molecular weights of 300-500 g·mol -1 and more, and with saturation pressure of 10 -4 -10 -8 Pa and lower can form fine films and particles (e.g., 1 μm in diameter), which could live in the environment for many hours, days and weeks [23]. Pesticides are reputed to be the ecologically dangerous air and vegetation contaminants.…”

Spatial and temporal distribution of current-use pesticides in ambient air of Provence-Alpes-Côte-d’Azur Region and Corsica, France

“…Ubiquitous in today's farming culture, pesticides are used to protect the crops against weeds (herbicides), fungi (fungicides), or insects (insecticides), and to ensure a regularity in agricultural production necessary for people's diet. Not surprisingly, the current agricultural practice is considered as the main source of atmospheric pesticide pollution (Samsonov et al, 1998;Lichiheb et al, 2015), even if other important sources of pesticide pollution include production, industrial, and urban applications.…”

Câmara de volatilização: uma alternativa para avaliação da eficiência de amostragem de &#945;- e <FONT FACE=Symbol>&#946;</FONT>-endossulfam em fase gasosa

“…2,4 De uma maneira geral, estima-se que cerca de 30-50% da quantidade de agrotóxicos aplicada nas lavouras pode ser perdida para a atmosfera nas formas de vapor, adsorvidas em material particulado ou como aerossol. 9 Os relatos da presença de agrotóxicos na atmosfera datam do final dos anos 50, ocasião em que o uso de organoclorados, tais como DDT, lindano e dieldrin era bastante intenso. 10 Apesar dos primeiros trabalhos sobre contaminação atmosférica por agrotóxicos datarem de mais de meio século, a quantidade destes ainda é relativamente escassa em comparação àqueles envolvendo as matrizes água e solo.…”