7/23/2019 What Are Nitrogen Oxides

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What is it?

Nitrogen dioxide is an irritant gas, which at high concentrations causes

inflammation of the airways.

When nitrogen is released during fuel combustion it combines with oxygen

atoms to create nitric oxide (NO). This further combines with oxygen to create

nitrogen dioxide (NO2). Nitric oxide is not considered to be haardous to

health at ty!ical ambient concentrations, but nitrogen dioxide can be.

Nitrogen dioxide and nitric oxide are referred to together as oxides of nitrogen

(NOx).

NOx gases react to form smog and acid rain as well as being central to the

formation of fine !articles ("#) and ground le$el oone, both of which are

associated with ad$erse health effects..

%ources of NOx "ollution

NOx is !roduced from the reaction of nitrogen and oxygen gases in the air

during combustion, es!ecially at high tem!eratures. &n areas of high motor

$ehicle traffic, such as in large cities, the amount of nitrogen oxides emitted

into the atmos!here as air !ollution can be significant. NOx gases are formed

whene$er combustion occurs in the !resence of nitrogen ' e.g. in car engines

they are also !roduced naturally by lightning.

%ee more at* htt!*++www.ico!alnoxite.co.u+nox!roblem+nox

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 The Hong Kong SAR and Guangdong Provincial Governments have long been

collaborating to improve the air quality in thePearl River Delta

(PRD Regionnote!" #ver the past years$ the t%o Governments signi&cantlyreduced the emissions o' 'our maor pollutants$ namely S#)$ *#+$ RSP and ,#-"

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At the meeting o' Hong Kong.Guangdong /oint 0or1ing Group on Sustainable

Development and 2nvironmental Protection held in *ovember )3!)$ both sides

endorsed a ne% set o' emission reduction targets4ranges up to )3)3$ using )3!3

as base year" 5oth sides have been implementing additional pollution control

measures on this basis 'or bringing continuous improvement to the regional air

quality"

6n order to achieve the emission targets4ranges set 'or )3!7 and )3)3$ Hong

Kong has implemented the 'ollo%ing 1ey measures8

• -ompleted in April )3!9 a one.o: subsidy scheme to replace the catalytic

convertors and o+ygen sensors o' petrol 4 ;ique&ed Petroleum Gas (;PG

ta+is and light buses<

• ;aunched in =arch )3!9 an incentive.cum.regulatory scheme to phase

out pre.2uro 6, diesel commercial vehicles by end )3!><

• Strengthened the inspection and maintenance o' ;PG and petrol vehicles

'rom September )3!9 by deploying roadside remote sensing equipment

to detect e+cessive emissions 'rom petrol and ;PG vehicles<

•  Tightened the limit on sulphur content o' locally supplied marine light

diesel to 3"37? in April )3!9<

•  Tightened progressively the emission caps on po%er plants$ %ith the

latest emission caps e:ective in )3!>< and

• -ontinued to en'orce the Air Pollution -ontrol (,olatile #rganic-ompounds Regulation to control volatile organic compounds emission

'rom paints$ printing in1s$ adhesives$ sealants and selected consumer

products"

#ther 1ey measures in the pipeline include8

• =andating the use o' lo%.sulphur 'uel 'or ocean.going vessels berthing in

Hong Kong 'rom ! /uly )3!7 under the Pollution -ontrol (#cean Going

,essels (@uel at 5erth Regulation<

• -ontrolling the emissions 'rom o:.road mobile machinery 'rom !September )3!7 under the Air Pollution -ontrol (*on.road =obile

=achinery (2mission Regulation< and

• Retro&tting 2uro 66 and 2uro 666 'ranchised buses %ith selective catalytic

reduction devices to reduce their emissions"

Such measures %ill help us to achieve the emission reduction targets 'or )3!7

and )3)3$ and to meet broadly the e+isting Air uality #bectives by )3)3"