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Explora: Environment
and Resource Leaf burning air pollution

alkanes tended to be higher for leaf as opposed to brush
burning, with production of C alkanes being much
27
higher for leaf as compared to brush burning (with Total PAHs or polycyclic aromatic hydrocarbons 85 45
mean emissions of 113.2 mg/kg of leaves burned versus
13.4 mg/kg of brush burned). Table 1, which is an abridged
2
version adapted from published literature, provides an
interesting comparison between air pollutants produced Benzo(a) pyrene 1.5 0.3
by leaf burning and other forms of biomass burning. The
2,25
exact reasons for differences in air pollution between the
various forms of biomass burning are not precisely known, Total alkanes 83 252
but could be due largely to differences in temperature and
moisture during burning, as well as differences in fuel type.
For example, leaves have higher carbon content than other
parts of a tree.
Further work by the Noblet et al. involved liquid Monosaccharide anhydrides including levoglucosan, mannosan, and galactosan 1 752 2 040
26
chromatography and gas chromatography-high resolution
mass spectroscopy on emissions from burning of fallen
leaves, hedge trimmings, and wood logs. While there were
many similarities in the emissions produced between CO 63 000 102 000 135 000 127 000 89 000 93 000 182 000 67 000
leaf, brush, and wood burning, this study did identify
31 possible markers for green waste burning including
neophytadiene (gram molecular weight [GMW]: 278), CO 2 1 663 000 1 585 500 1 548 000 1 489,000 1 637 000 1 643 000 1 563 000 1 710 000
rimuen (GMW: 272), and δ and ϓ tocopherols (GMW:
403 and 417, respectively). 26
The amounts of residential leaf and brush that are burned PM 2.5 7 170 6 260 14 800 15 300 12 700 9 100 20 000 11 900
are not precisely known, but are considerable even in areas
where community composting services are available and/
2
or leaf burning bans are imposed. In 1997, the U.S. EPA PM 10 33 400 34 700
estimated that about 35 million tons of yard trimmings
were produced annually in the U.S., of which about 28% Elemental NA 0.2
was burned. In 2018, the same agency estimated that carbon
27
about 35.5 million tons (about 32.4 million metric tons) of
yards waste entered the municipal waste stream annually,
of which about 22.3 million tons was composted/recycled Total particulate carbon 21 800 24 700 3 000 10 600
(63%), 10.6 million tons was landfilled (30%), and about
2.6 million tons (7%) was combusted for energy recovery.
28
However, the amount of leaves and yard trimmings that
were burned in the open before entering the municipal Type of burning Combustion Chamber 1000 m 3 Various mechanisms
waste stream was not estimated. Eades et al. estimated test
29
28
in 2020 that the average rural English household burned
about 180 kg of garden waste per year. Gaurav estimated Table 1. Emissions produced by burning of various biomass materials
that, in 2010, leaf/brush burning emitted about 700 million Notes: The emissions are expressed as milligrams per kilogram burned.
kilograms (700,000 metric tons) of PM annually in India,
2.5
which is about 12% of the PM emitted by all sources in Hedge trimmings-Wood and Mixed fallen leaves-Mixture
2.5
India (residential burning wood, straw, dung, and coal Material burned oak, beech, hornbeam Temperate forest Peatland burning
for heating and cooking creates about 57% of the PM mixed leaves Crop residue Pasture grass Boreal forest Tropical forest Chaparral
2.5
emitted in the country). 30 Savanna
Both wildfires and leaf burning also produce large
quantities of brown and black smoke which can absorb
significant quantiles of sunlight and add to global warming Study Noblet et al. (2021) 2 Akagi et al. (2011) 25
by climate-forcing mechanisms. 31-33

Volume 1 Issue 1 (2024) 3 doi: 10.36922/eer.4040