Limestone in Jordan has a broad distribution, occurs in different stratigraphic levels with several meters of thickness, and presents with huge reserves in many parts of the country as shown in Figure 1. It is used for construction of composite wall for aesthetic purposes, such as thin polished tiles (marble), floor tiles and monumental architecture or dry stonewalling that characterizes the countryside of Jordan buildings, in addition to its uses as aggregates [1] . The limestone production is a very important economic sector in Jordan [2] . The limestone production in Jordan is shown in Figure 2. Many of the limestones belong to the quarries that are located near to urban territories in the Irbid district (Sammad area), north of Jordan. Most of the mining operation is mainly open cast mining. The mining activities emit air pollutants such as particulate matter (PM) into the air through different sources and emissions. The mining activities have fugitive dust sources that contribute to increasing air quality levels in the urban areas around the quarries. Most of the limestone aggregates are a mixture of grains resulting from fragmentation of rocks due to crushing and milling industry by different machines that can be subdivided into two types: coarse aggregates and fine aggregates (microns to few mm).

The authorities in Jordan are developing air quality plans to bring PM10 concentrations down to healthful levels. These plans include a variety of regulations and programs to reduce emissions, including dust control for transport, mines and quarries through using PM10 and PM2.5 [3] [4] . The Jordanian Standards of Ambient Air

Quality (JSAAQ) including the standard of PM10 was used in this study. Regarding to this standard, the maximum allowable concentration of PM10 for duration of 24 hours is up to 120 µg/m³, and annually is up to 70 µg/m³.

Airborne particulate matter represents one of the most pollutant factors in quarrying activities. PM10 pollution consists of very small liquid and solid particles floating in the air. Of greatest concern to public health are the particles small enough to be inhaled into the deepest parts of the lung. These particles are less than 10 microns in diameter and are known as PM10. This includes fine particulate matter known as PM2.5. PM10 is a major component of air pollution that threatens both our health and our environment. PM10 can increase the number and severity of asthma attacks, cause or aggravate bronchitis and other lung diseases, and reduce the body’s ability to fight infections [5] - [12] . Of greatest concern are recent studies that link PM10 exposure to the premature death of people who already have heart and lung disease, especially the elderly [13] [14] .

Many areas in Jordan suffer from elevated levels of PM10. One potentially significant source of the observed PM10 is the resuspension of road dust and dust causes by mining activities in the vicinity of limestone quarries as shown in Figure 3. This is a problem in our cities, rural areas and pristine areas such as national parks, forests and vegetation. Amount of 150.000 ton of limestones and aggregates are exploited from these areas and most of the quarries are scattered throughout the urban areas. Their exploration, excavation, and mineral processing directly infringe upon and affect the other natural resources like land, water, air, flora and fauna, which are to be conserved and optimally utilized in a sustainable manner. The environmental problems associated with limestone quarrying and mining are diverse. The removal of vegetation and topsoil and increasing of overburden and waste will affect the landscape of these areas.

To obtain data and to assess the impact from these sources, PM10 road dust resuspension factors near Sammad, SW Irbid were measured. Measurements included PM10 mass, particle size distributions, wind speed, wind direction and rainfall. After the results were presented, the conclusions discussed the state of PM10 concentration regarding the Jordanian Ambeint Air quality Standard (JS-1140/2006) through the measured period from January 2009 to November 2009.

The methodology adopted in this study is based on the specific parameters through the period from January 2009 to November 2009. The domain of the present analysis covers all the limestone quarries area and the most important urban areas around them. The data of information of the air quality of PM10 have been taken from Mobile station which belongs to Natural Resources Authority (NRA). The meteorological information has been used based on data of Yarmook University station and Ras Munif. The emission inventories were based on the EPA AP-42 emission factors [15] , and the amount of activities were reported by the NRA and mining companies. Based on these data the following activities have been carried out:

Ÿ Comparing the measured concentrations of PM10 with the Jordanian standard.

Ÿ To prepare analysis of trends and correlation between air quality and meteorological stations.

Ÿ Using avilable dispersion models for Sammad area (Shatana and Rahma), then applying the results at the similar areas.

Ÿ Setting up an air quality dispersion model for some of the mining areas in Jordan and comparing of the calculated and measured concentrations.

Ÿ Analyzing and discussing the given results.

Ÿ Methods of mitigation and recommendation

EPA-AP42 document have been used to calculate the emissions factor. The factors are used for each activity [15] . The source and name of the emission factor with its reference is shown in Table 6.

The results of analysis are revealed to the major conclusions. By comparing the measured concentrations of PM10 with the Jordanian standard at first station area (Shatana), it can be noticed that during the winter season the concentration of PM10 is equal to or below the Jordanian standard, while during summer season the concentration of PM10 is over the Jordanian standard with recording the data of 24 hours. With recording the data at day work (from 6 a.m. to 6 p.m.), from 7 March to 3 April, the concentration of PM10 was over the Jordanian standard (with about 10 µg/m³). In summer season, the concentration of PM10 was over the Jordanian standard

(with more than 50 µg/m³). From October to December, the concentration of PM10 rises with small amount over the Jordanian standard. In other seasons, the concentration of PM10 is equal to or below the Jordanian standard. With recording the data at night as shown in the graphics, the concentration of PM10 was over the Jordanian standard only in summer time (June-July).

By comparing the measured concentrations of PM10 with the Jordanian standard at second station area (Rahma), it can be noticed that during the winter season the concentration of PM10 is equal to or below the Jordanian standard (January to May, and December), with recording the data of 24 hours, while during summer season the concentration of PM10 is over the Jordanian standard from May to November.

With recording the data at day work (from 6 a.m. to 6 p.m.) during summer season, the concentration of PM10 is over the Jordanian standard (from April to November). During winter season, the concentration of PM10 is below the Jordanian standard (from December to April). From November, the concentration of PM10 starting decreases. With recording the data at night, as shown in the graphic, the concentration of PM10 is below the Jordanian standard during the year.

Comparing the measured concentration of PM10 in both areas with the Jordanian standard, it can be concluded that the concentration of PM10 increases in summer season during day work. The range of PM10 value was 120 - 140 µg/m³, and the value of PM10 during other seasons was around the Jordanian standard (70 µg/m³).

Analysis of trend relation between the measured concentration of PM10 and wind speed at both station areas (Shatana and Rahma) for 24 hours during 24 hours, day work and at night, as shown in Figures 13-18, indicates the trend relationships between the measured concentrations of PM10 and the wind speed for different periods of time. It can be noticed that when the wind speed increases, the concentrations of PM10 decrease in winter season, while in summer season when the wind speed increases the concentrations of PM10 increase.

From the analysis trend and relation between rainfall and the concentration of PM10, it can be concluded that the measured concentration during winter season is below or around the Jordanian standard (70 µg/m³), while in the summer (Jul. and Aug.) the concentration increases (as shown in Figure 19). It can be noticed from the obtained data as shown in Table 4 and Table 5 that when the rainfall is increased during winter seasons the average of PM10 decreases, while when the rainfall decreases in the summer season the average of PM10 increases.

Forward trajectories have shown that pollutants attributed to the mining activities inside the quarries, and distributed outside the mining areas depend on the wind speed and wind direction. Comparing the measured concentration of PM10 with rainfall, it can be assumed that the concentration of PM10 decreases in winter season during day work. Figure 20 shows the R² correlation factor for the wind speed and concentrations. The correlation factor at Shatana station is around 0.6395, while the correlation factor at Rahma station is around 0.4095. It can be assumed that the trend is very clear and more affective in Shatana station, while in Rahma station the trend is relatively less affective.

It can be concluded that the dust has effects on the health and safety of workers in mines and residents living in the urban areas near the quarries, as well as on the biodiversity in the region. Monitoring and follow-up measurements of dust levels in the atmosphere are important elements to preserve the environment in these areas. The authorities in Jordan are developing air quality plans to bring PM10 and PM2.5 concentrations down to healthful levels. These plans include a variety of regulations and programs to reduce emissions, including dust control for transport, mines and quarries. However, there are some procedures that can lead to reduce the threat of PM10 such as: 1) scheduling the activities of mining, loading, transport and dumping to coincide with favourable atmospheric conditions; 2) to avoid blasting under unfavourable wind and atmospheric conditions; 3) wet drilling will minimize and mitigate the dust emissions; 4) application of water during topsoil stripping may be affective, and many of mining activities can be scheduled during the period when the soil has the optimal moisture; 5) minimizing of exposed areas through careful planning; 6) rehabilitation and revegetation are continuous work and will help in mitigation of pollution; 7) to limit the speed of vehicles on haul roads and to drive with limited speed on unpaved roads, and to spray water during mining activities and during transportation; 8) to be involved with air quality improvement programs in the urban areas near to Sammad and other similar areas around and to work with local agencies to develop strategies that will further reduce the PM10 emissions and to save the biodiversity in the studied area.

This research was supported by Natural Resources Authority, Jordan. The contents are sole responsibility of the authors. The authors would like to thank anonymous reviewers for their constructive comments.

All authors conceived of the research and wrote the paper. They analyzed the data, discussed and commented the results and implications.

The authors declare no conflict of interest.