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The Pollutant Standards Index (PSI) is a type of air quality index used in Singapore, which is a number used to indicate the level of pollutants in air.Initially PSI was based on five air pollutants, but since 1 April 2014 it has also included fine particulate matter (PM 2.5).
While an AQI of 50 from day 1 to 182 and AQI of 100 from day 183 to 365 does provide an annual average of 75, it does not mean the pollution is acceptable even if the benchmark of 100 is deemed safe. Because the benchmark is a 24-hour target, and the annual average must match the annual target, it is entirely possible to have safe air every day ...
Particulate matter (PM), particularly PM2.5, was found to be harmful to aquatic invertebrates. [41] These aquatic invertebrates include fish, crustaceans, and Mollusca. In a study by Han et al, the effects of PM<2.5 micrometers on life history traits and oxidative stress were observed in Tigriopus japonicus.
The guidelines stipulate that PM 2.5 should not exceed 5 μg/m 3 annual mean, or 15 μg/m 3 24-hour mean; and that PM 10 should not exceed 15 μg/m 3 annual mean, or 45 μg/m 3 24-hour mean. [2] For ozone (O 3 ), the guidelines suggest values no higher than 100 μg/m 3 for an 8-hour mean and 60 μg/m 3 peak season mean. [ 2 ]
Air pollution measurement is the process of collecting and measuring the components of air pollution, notably gases and particulates. The earliest devices used to measure pollution include rain gauges (in studies of acid rain ), Ringelmann charts for measuring smoke , and simple soot and dust collectors known as deposit gauges . [ 1 ]
Particulates or atmospheric particulate matter (see below for other names) are microscopic particles of solid or liquid matter suspended in the air.The term aerosol refers to the particulate/air mixture, as opposed to the particulate matter alone, [1] though it is sometimes defined as a subset of aerosol terminology. [2]
Critics maintain that congestion pricing is not equitable, places an economic burden on neighboring communities, and adversely affects retail businesses and general economic activity. There is a consensus among economists that congestion pricing in crowded transportation networks, and subsequent use of the proceeds to lower other taxes, makes ...
Emission standards are the legal requirements governing air pollutants released into the atmosphere.Emission standards set quantitative limits on the permissible amount of specific air pollutants that may be released from specific sources over specific timeframes.