Air quality in Newcastle: Spring 2015 1

Spring 2015

Air quality in Newcastle: Spring 2015

Air quality in the Newcastle region from 1 September to 30 November 2015 was generally good.

Levels of fine particulate matter PM2.5 (particles less than or equal to 2.5 microns in diameter),

nitrogen dioxide (NO2), sulfur dioxide (SO2) and ammonia (NH3) were all below benchmark

concentrations.

Daily average levels for particulate matter PM10 (particles less than or equal to 10 microns in

diameter) were above the 50 µg/m3 benchmark on 20 days during spring (3–9 and 28–29 October

and 5, 12, 19–20, 22-23 and 25–29 November).

o Beresfield and Carrington recorded elevated levels on one day (26 November) with daily

averages of 57.5 and 56.4 µg/m3 respectively.

o Mayfield recorded elevated levels on three days (19 and 26–27 November) with daily

averages up to 53.8 µg/m3 on these days.

o Newcastle recorded elevated levels on two days (25-26 November) with daily averages up to

54.8 µg/m3.

o Elevated levels on 2627 November may have been influenced by a bushfire at Stanford

Merthyr, northwest of Newcastle1.

o Stockton recorded elevated levels on all 20 days (with maximum values ranging from 51.0 to

101.4 µg/m3 and averaging 65.1 µg/m3 on these days). The maximum PM10 level occurred on

4 October during seven consecutive days of elevated particle levels. During this time,

elevated levels occurred under north-easterly to north-westerly winds. Stockton particle levels

may be influenced by sea salt spray from onshore winds, becoming more predominant during

this warmer season.

Days above benchmark concentrations

The most widespread particle event occurred from 25–27 November, when all sites except Wallsend

recorded days with PM10 levels over the 50 µg/m3 benchmark. A 58-hectare bushfire at Stanford Merthyr,

(approximately 20 kilometres northwest of Newcastle) starting on 26 November may have elevated

particle levels during this period. Winds on this day were generally north-westerly with a southerly

change in the evening.

Table 1: Number of days above the relevant benchmarks – spring 2015

Station PM10

daily [50 µg/m3

benchmark]

PM2.5

daily [25 µg/m3

benchmark]

SO2

hourly [20 pphm

benchmark]

SO2

daily [8 pphm

benchmark]

NO2

hourly [12 pphm

benchmark]

NH3

hourly [46 pphm

benchmark]

Beresfield 1 0 0 0 0 -

Carrington 1 0 0 0 0 -

Mayfield 3 0 0 0 0 -

Newcastle 2 0 0 0 0 -

Stockton 20 0 0 0 0 0

Wallsend 0 0 0 0 0 -

µg/m3 = microgram per cubic metre and pphm = parts per hundred million by volume (i.e. parts of pollutant per hundred million parts of air) - = not monitored

1 Rural Fire Service ICON database

Air quality in Newcastle: Spring 2015 2

Daily time series plots

Daily average PM2.5 concentrations and one hour maximum concentrations of NO2, SO2 and NH3

remained below the benchmarks.

Daily average PM10 concentrations were above the benchmark on 20 days throughout spring 2015,

predominantly at Stockton which is influenced by sea salt spray under onshore winds. Elevated PM10

levels at a number of sites late in November may have been influenced by a nearby bushfire. More

information on the elevated days at Stockton from 3–9 October are included in a detailed section below.

Figure 1: Daily average PM10 during spring 20152

Figure 2: Daily average PM2.5 during spring 2015

Figure 3: Daily 1-hr maximum NO2 during spring 2015

Figure 4: Daily 1-hr maximum SO2 during spring 2015

Figure 5: Daily 1-hr maximum NH3 during spring 2015

2 Daily PM10 and PM2.5 data are not available at Stockton on 30 October, due to a scheduled calibration.

Air quality in Newcastle: Spring 2015 3

Pollution roses

The seasonal pollution rose maps show that a small percentage of elevated hourly PM10 levels (>75 µg/m3)3

occurred at some sites during spring, in particular at Stockton. These occurred predominantly with winds from

the northeast, but also on occasion from north to northwest. Hourly PM2.5 levels generally remained low

during the season.

Figure 6: Hourly PM10 pollution roses for the Newcastle region for spring 2015

Figure 7: Hourly PM2.5 pollution roses for the Newcastle region for spring 2015

3 Note: There are no standards for hourly PM10/PM2.5 in the National Environment Protection (Ambient Air Quality) Measure (Air NEPM). The value of 75 µg/m3 was chosen to highlight only those hours with relatively elevated hourly PM10 levels.

Air quality in Newcastle: Spring 2015 4

Seasonal comparisons

This section compares air quality levels in spring 2015 with previous spring seasons, where data were

available. Monitoring at Stockton commenced in October 20124 and at Mayfield and Carrington in August

2014. Monitoring of PM2.5 at Newcastle commenced in December 2013.

All days were below benchmark concentrations for NO2, SO2 and NH3 in spring during the past three years at

Beresfield, Newcastle, Stockton and Wallsend and since monitoring began at Carrington and Mayfield.

All days were below the PM2.5 daily average benchmark during spring 2015. In the previous two years, there

was one day over the benchmark in 2014 and eight days in 2013.

Beresfield and Carrington recorded one day with average concentrations above the PM10 benchmark in

spring 2015, Newcastle recorded two days, Mayfield recorded three days, and Stockton recorded 20 days.

This result was comparable to previous spring seasons.

Figure 8: Number of days above the PM10 and PM2.5 benchmarks: spring 2015, 2014 and 2013

Stockton

The Stockton monitoring site continued to record

a higher number of days over the PM10

benchmark compared to other sites in the region.

In spring 2015, elevated hourly PM10 levels

(>75 µg/m3)5 occurred 9.8% of the time,

predominantly under onshore north-east winds.

This indicates the potential contribution of sea salt

spray to the particle levels. More information on

the composition of airborne particles in the region

is being obtained through the Lower Hunter

Particle Characterisation Study6.

Some elevated levels also occurred under north-

west winds, with the majority occurring from 4–7

October. Other sites in the region also had

elevated levels during this time.

Figure 9: Stockton spring 2015 pollution rose – proportion of hourly averaged PM10 levels >75 µg/m3 by wind direction

4 Orica originally undertook Stockton air quality monitoring; from October 2014 it was undertaken by the Office of Environment and Heritage as part of the Newcastle Local Air Quality Monitoring Network. 5 75 µg/m3 was chosen as a lower cut-off point to highlight only those hours with relatively elevated hourly PM10 levels. There is no standard for hourly PM10 in the National Environment Protection (Ambient Air Quality) Measure (Air NEPM).

6 Lower Hunter Particle Characterisation Study

Air quality in Newcastle: Spring 2015 5

Meteorological summary

Rainfall and temperature7

The Newcastle region experienced ‘average’ rainfall during spring. Rainfall was around 100–200 millimetres

more in spring 2015 compared to spring 2014 and 100–200 millimetres less than spring 2013. Maximum

temperatures were above average, while minimum temperatures reached ‘highest on record’ during the

season. Numerous records were broken in New South Wales during an early-season heat wave in October8,

The Bureau of Meteorology report that during this heatwave Newcastle saw four consecutive days with

temperatures over 30°C, which is unprecedented at this site.

Figure 10: NSW rainfall deciles - spring 2015

Wind

The winds were variable at all sites during spring 2015, which is typical for this transitional season, where

predominant winds change from north westerly in winter to easterly in summer.

Figure 11: Wind rose map for the Newcastle region for spring 2015

7 Rainfall and temperature information are from the Bureau of Meteorology seasonal climate statement and climate maps accessed

January 2016. 8 Special Climate Statement 52 - Australia's warmest October on record

Air quality in Newcastle: Spring 2015 6

Stockton particle event – 3 to 9 October 2015

Stockton recorded PM10 particle levels over the 50 µg/m3 benchmark for seven consecutive days from 3

to 9 October 2015, a period of record breaking early season extreme heat across southern Australia9.

Daily averages ranged from 53.0 µg/m3 to 101.4 µg/m3 during this period. Other sites in the Newcastle

region were also elevated during this time, particularly on 6–7 October, when daily averages were close

to the benchmark (Figure 12). Daily PM2.5 levels remained below the 25 µg/m3 benchmark during this

period, although levels reached 22.3 µg/m3 at Stockton on 4 October (Figure 13).

The PM10 pollution rose (Figure 15) shows that elevated hourly PM10 levels predominantly occurred

under north-westerly to north-easterly winds, with the highest levels experienced at Stockton.

From 3–6 October winds were generally light to moderate north-westerly during the day followed by

north-easterly sea breezes in the afternoon at Stockton (Figure 14). Elevated particle levels were seen at

varying times of the day over this period. A southerly change occurred on 7 October, followed by

elevated levels under onshore winds. Sea salt spray is the most likely contributor to elevated levels when

winds were onshore north-easterly, while industrial sources may have contributed when winds were

north-westerly.

There were reports of only very small fires in or near the Newcastle region during this period10.

Figure 12: Daily average PM10 from 2 to 10 October 2015

Figure 13: Daily average PM2.5 from 2 to 10 October 2015

Figure 14: Stockton time series plot for PM10, wind direction and wind speed from 3 to 9 October 2015

9 Special Climate Statement 52 - Australia's warmest October on record 10 RFS ICON database

Air quality in Newcastle: Spring 2015 7

Figure 15: Hourly PM10 pollution rose map for the Newcastle region from 3 to 9 October 2015

Network performance

The target network performance is at least 95% available data for all parameters. For NO2 and SO2, due

to daily calibrations, the maximum online time that can be attained is 96%.

Table 2: Online performance (%) during spring 2015

Station Particles PM10

daily

Particles PM2.5

daily

Gases SO2

hourly

Gases NO2

hourly

Gases NH3

hourly

Meteorology Wind

hourly

Beresfield 100 98 94 94 - 99

Carrington 98 98 94 87 - 100

Mayfield 97 96 96 96 - 93

Newcastle 98 96 93 94 - 100

Stockton 99 99 95 95 95 100

Wallsend 98 98 95 91 - 100 - = not monitored

The overall reduced online times were mainly due to:

Carrington – NO2 instrument problems and associated maintenance checks (seven days)

Wallsend – NO2 instrument problems (four days)

Mayfield – Wind instrument intermittent earthing problem following a lightning strike (seven days).

© 2016 State of NSW and Office of Environment and Heritage

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ISSN 2206-0421 OEH 2016/0130 February 2016